Manual Tong

ABSTRACT

A manually or mechanically/hydraulically operable tong of light weight and high load capacity by means of a multi-layer interlocking construction achieved by cutting the shapes from plate steel by known means, assembling the plate sections in suitable order, and retained with each other by cylindrical steel pins ( 8 ) forming a multi hinged tool capable of engaging the job circumference on two or more points equally via replaceable jaw dies ( 15 ) retained radially and axially.

FIELD OF INVENTION

This invention has particular application to the mining, rock drilling,waterwell drilling, and horizontal drilling industries, wherein theenormous torque loads encountered often create great difficulty whenunscrewing drill stems and other drilling tools as retracting from theborehole. However, it is envisaged that the invention will be beneficialto other industries where circumferential high force gripping ofcylindrically shaped objects is required.

PRIOR ART

In reference to pipe handling tools used in the drilling industry, thereare those generally referred to as ‘pipe tongs’ or ‘casing tongs’. Manyof these are fully or semi automated units and are specific to the oiland gas drilling industry, and not within the scope of the presentinvention. Prior art tools relating to the present invention are moreaccurately described as ‘manual tongs’, ‘chain tongs’, ‘Petol tongs’,‘BV tongs’, ‘Rapspan tong’, ‘pipe wrench’, or ‘stilson’, and areidentified by having a handle, or lever, which serves to permit loadbeing applied by hand, and, if so designed, also permitting theapplication of mechanical force to that lever.

Prior art tools rely heavily on the casting, forging, machining, andheat treatment processes as necessary to achieve the least practicableweight with the highest possible strength/torque/load capacity, sinceweight is a critical safety factor when large tools are to beman-handled, such as on waterwell and exploration mobile drillrigs. Ithas been common for several decades for manufacturers of these drills tofit as standard equipment an adjustable pipe wrench, modified by cuttingthe handle short, welding a lug to the shortened handle for attachmentto a hydraulic cylinder, for the purpose of applying high torque to thedrillpipe and drilling tools. Although relatively lightweight and easyto use, it is an inappropriate modification of a hand tool, and hasbecome the accepted norm within the industry, notwithstanding the welldocumented injuries resulting from this unsafe practice.

These types of breakages are without warning as the component, whetherfaulty or overloaded, suddenly fails and the tool flies apart, severelyinjuring any body in its path. U.S. Pat. No. 6,119,558 seeks to minimisethese injuries by the addition of a safety device in the case of suchfailures.

A well known and regarded tool is manufactured by Petol Tool Co, butthis tool also is not without its problems in that it is cumbersome toman-handle, and heavily reliant on expensive manufacturing techniques.

U.S. Pat. No. 5,957,010 seeks to alleviate the downside of the Petolwrench by making a somewhat lighter but equally strong tool, at a lowercost. Although achieving this to a degree, in today's ever-costconscious environment, it is still considered an expensive tool, duemainly to the extensive machining required in its manufacture.

DESCRIPTION

In one aspect the present invention relates to;

A method of manufacture for a tool designed for hand ormechanical/hydraulic force actuation of cylindrical pipe and similarobjects, and

A tool designed for hand or mechanical/hydraulic force actuation, amulti hinged circumferential gripping tool of multi layer/laminatedconstruction with replaceable jaws and means of axial retention of saidjaws, having

A handle assembly 1 consisting of a lever 2 and a head 3. The lever endhaving a hole 4 for the convenient attachment of mechanical forcedevice, usually a hydraulic cylinder. The head end having a hole 5suitably positioned as to be the pivot point about which mechanicaladvantage is applied to the tool.

The next component of the tool is of a shape 6 with holes 5 each end, aninner curved edge forming an arc 7, one end retained to the head end ofthe handle assembly by a steel pin 8, thereby the first hinge point ofthe multi hinged tool.

Subsequent components 9,10,11 are attached one to the other, in likemanner.

The last component 11 has a hole at one end for attachment to theprevious component, the other end has a heel 12, which is shaped tosuitably engage with the head 3. There may be more than one such heelcapable of engaging the head, for instance, if an object is of a smallerdiameter than the normal range of the tool, another heel would engagewith the head, thereby applying gripping and torsional force to thesmaller diameter. With reference to FIG. 3, the gripping range of thetool may also be increased by modification of at least one of components6,9,10,11, to incorporate at least one extra connection or pivot point17. The extra connecting pivot may be a hole requiring the removal ofthe steel pin to align the new hole and refit the pin, or it may be ahooked latch arrangement, not requiring the steel pin removal.

The tool may consist of a number of such layers as is practical.

In application, each of the hinged components will encompass part of thecircumference of the job, the head brought into contact with the heel,load applied to the lever causing a circumferential compression of thetool onto the job in conjunction with the torsional force being applied.

Jaws: most gripping tools are known to have some type of protruding,roughened or serrated surface, whether an integral part of the bodilysection, a replaceable component, an applied coating, fitted or fixed bymechanical means, welding, brazing, etc.

Some gripping tools designed for rotational engagement rely uponfrictional resistance alone, not having any visibly apparent grippingappendages.

It is envisaged that all known methods of gripping surfaces areapplicable to our tool, however, we have developed specific replaceablejaws, retained in rotation circumferentially by a dovetail-like cut-outin the tool section with a corresponding angular dovetail shape on thejaw.

In axial plane however, the retention of the jaw insert, that ispreventing the jaw from falling out, varies.

Prior art tools of solid body construction, as opposed to our multilayer steel plate construction, with removable/replaceable jaws, varyfrom having welded or bolted small steel plates as axial retainers,interference fit retaining pins, and spring loaded steel pins retainedwithin a countedrilled hole in the tool body, which is depressed, thejaw inserted, and the spring forcing the pin into a corresponding holein the jaw, thereby preventing the axial falling out of the jaw.

By means of the simple multi-layer design of the tool, the axialretention in the present invention is achieved by a threaded hole in thejaw body. With reference to FIG. 2, the assembly of the jaw to the toolis described: insert the jaw 15 into the corresponding dovetail 14 ofthe tool. The jaw is now retained radially but is free to drop outaxially with the tool in the horizontal plane. Now since the tool is ofa multi-layer plate construction, there are gaps between the platescorresponding to the plate thickness. Into the appropriate gapcorresponding with the aforementioned threaded hole in the jaw, isinserted a retainer 16, ideally a grub screw of suitable length, ofsimilar diameter as the gap dimension, and of matching thread size inthe jaw. Screwing the retainer into the back of the jaw far enough as tonot protrude the jaw teeth, but protruding the rear of the jaw as to beconstrained in the gap between the plates, hence simple and effectiveaxial location of the jaw. The retainer 16 may also be inserted from thefront, or gripping surface of the jaw 15.

Such a method permits quick and simple installment and replacement ofthe jaw.

The replacement jaw may be of the same or different thickness, therebyenlarging the scope of the tool to grip a larger range of diameters.

Overview: our claims relate to the style of design, method ofmanufacture, and subsequent advantages of that design and constructionover prior art tools of similar application. Some advantages of thisdesign and method of manufacture are:

Low capital equipment requirement for manufacture.

Design alteration, in the sense that different sizes are quickly andsimply made by scaling the drawing and cutting the shapes, nore-tooling.

The strength of the tool can be modified, i.e.; the tool can beconstructed of thinner plate to reduce the weight for the purpose ofease of handling or for a light duty application. Alternately it can bemade of thicker and or higher grade plate for heaviest duty application,even increasing, or decreasing the number of plates to alter thestrength and weight.

This method of manufacture is applicable to prior art tools of similarpurpose, and there is a significant cost and weight advantage, withoutloss of strength, in reconfiguring prior art tools to our style ofdesign and manufacture.

The construction of this tool, being of plate steel, is not asvulnerable to the violent breakages under load as prior art tools ofcast, forged, then heat-treated construction can be. These types ofbreakages are without warning as the component, whether faulty oroverloaded, suddenly fails and the tool flies apart, injuring any bodyin its path. Conversely, steel plate, by its tensile nature, will bendand buckle if overloaded, releasing the pent up energy of the torqueload force applied to the tool.

DRAWINGS

FIG. 1:

Is an orthographic view of the individual components in an assembledstate, showing the normally concealed contact point 13 of head 3 withheel 12 constrained between at least two numbers of plate section 6. Inthis view can be seen the dovetail cutouts 14 which subsequently locatethe jaw 15.

FIG. 2:

Shows a preferred embodiment of the invention in the horizontal planewith the jaw 15 and retainer 16, installed.

A load applied to lever 2 in a counter-clockwise direction will pivothandle assembly 1, consisting of a combination of lever 2 and head 3,about its pivot pin 8, to apply clamping force at 13, thereaftergripping and rotating the job.

FIG. 3:

Is an orthographic view of an embodiment of the invention, without jawsfitted, permitting a greater scope of adjustment by the modification ofat least one of components 6,9,10,11, to incorporate at least oneadditional connection point 17.

FIG. 4:

For illustration and clarity, is provided a photograph of a preferredembodiment of the invention.

The scope and ambit of the invention have been clearly described herein,variations could be made by persons skilled in the art without deviatingfrom that inherent ambit and scope, and any such variations andmodifications are deemed inclusive.

1-5. (canceled)
 6. A circumferential gripping tool comprising aplurality of gripping segments, each segment being formed from pluralsteel plates, the segments being interconnected by hinge pins atrespective ends thereof, the plates of adjacent sections beinginterleaved at said ends.
 7. A circumferential gripping tool accordingto claim 6, wherein in each segment, the plural steel plates areidentical to one another, and further comprising workpiece grippingmeans on at least one of said segments, and a handle connected to atleast one of said segments and engaging another of said segments in sucha way as to apply a crushing force to a workpiece when a force isapplied to said handle.
 8. A circumferential gripping tool according toclaim 7, wherein said workpiece gripping means comprise dies
 9. Acircumferential gripping tool according to claim 8, wherein said handlecomprises a stack of metal plates welded together to form a rigid whole,said handle being attached to at least one of said segments by one ofsaid steel pins.
 10. A circumferential gripping tool according to claim6, wherein at least one of said segments has at least one additionalhinge hole providing an extended range of tool size.